Known methods of bonding a ceramic to a metal involve the use of interlayer materials which either melt at the bonding temperature, such as a braze, or which involve special coating processes for the material surfaces to be bonded, such as pre-coating the surfaces with an activating material. In some methods of bonding, an interlayer material having a composition that approximates the composition of the initial metal bonding surface is utilized, such as disclosed by Lasater (U.S. Pat. No. 6,221,513 B1). Lasater describes a method for forming a hermetically sealed bond for use in implantable medical devices. Hill (U.S. Pat. No. 3,594,895) described another approach to forming a ceramic to metal seal.
Cusano (U.S. Pat. No. 3,994,430) disclosed a method of directly bonding metal to ceramic substrates wherein a very thin layer of an interlayer material is placed between the metal and the ceramic to be bonded. The system is heated in an inert atmosphere to a temperature between the eutectic temperature of the interlayer material and the melting point of the metal. Cusano focused on bonding copper to a ceramic substrate, such as alumina or beryllia.